OXIDATIVE CLEAVAGE OF CYCLOPROPANES .4. KINETICS OF CLEAVAGE OF ARYLCYCLOPROPANES BY MERCURIC ACETATE

The kinetics of cleavage of six arylcyclopropanes by mercuric acetate in acetic acid have been examined. The reaction is over-all second order, first order in each reactant. Activation parameters have been determined from the rates of the reactions at 25, 50, and 75°. Electron-releasing substituents facilitate the reaction. A correlation of the second-order rate constants and has been obtained for the substituents p-MeO, p-Me, m-Me, H, p-Cl, and m-Cl with p = — 3.2 at 50°. Under the reaction conditions the phenylcyclopropane-mercuric acetate adduct is stable. For the slow reactions, with electron-withdrawing substituents on the aryl ring, a side reaction of mercuric acetate leads to some analytical complications. Initial rate studies and the use of excess concentrations of cyclopropanes allow the circumvention of this difficulty. The cleavage reaction is postulated to involve electrophilic attack of mercuric acetate on the cyclopropane ring. There are similarities between the cleavage of cyclopropanes and the oxymercuration of olefins. © 1968, American Chemical Society. All rights reserved.